Shares of Apple (NASDAQ:AAPL) closed flat on Thursday, despite hedge fund giant Bill Ackman saying saying he does not want to buy Apple because it was incredibly hard to value. “The problem with Apple is it’s hard to predict cash flows over the next fifty years, or even the next five years,” Ackman said. “A watch sounds cool, but you know, what is the next thing that’s really going to drive the next stage in the business?”